The effects of echinatin and its related compounds on the mitochondrial energy transfer reaction.

To investigate the mechanism by which various biological action of licorice root are brought about, the effects of echinatin as a small constituent of Glycyrrhiza echinata and several related compounds on mitochondrial energy transfer reactions were examined. The results obtained were as follows: 1) Echinatin, 4'-hydroxychalcone, chalcone and 3,4'-dihydroxychalcone at a low concentration cause deterioration of respiratory control and oxidative phosphorylation of isolated rat liver mitochondria. 2) Chalcone and 4'-hydroxychalcone stimulate both latent and DNP-ATPase activity of mitochondria. Echinatin inhibits DNP-ATPase activity while stimulating range latent ATPase activity in the low concentration. 3) Chalcone and 4'-hydroxychalcone induce a rapid potassium release from mitochondrial vesicles, while echinatin and 3,4'-dihydroxychalcone have lesser effect than the former two substances. From these results, it can be concluded that echinatin and several related compounds disturb the mitochondrial energy transfer reactions and membrane permeability.